bcd
- 22nd March 2008, 08:02
Hi All,
I am currently working on an LED dimmer using a MOSFET on the PWM output of a 16F87 - I have some IRF540A devices that I am using with a 1k res from the PWM out to Gnd as recommended in this thread - http://www.picbasic.co.uk/forum/showthread.php?t=2782.
What I am concerned about is that these are not Logic Level MOSFETs and I am mighty confused about the optimum drive for the MOSFET.
Based on a lot of google work and some stuff I have read I think I might have a problem with not enough drive to turn the Mosfet Hard On. I want to scale this up to do ~5A, but I am concerned that as I am only driving them with 5v that they might not be fully tuned on and this will cause the Ron to rise and also reduce the total current rating.
I know you could just say "Get some logic level mosfets", but here in Australia it is hard to find them without paying $8-9 each.
So any of you analog guys want to comment on driving ~5A from a 5v logic out on a IRF540A ??
bill.
I am currently working on an LED dimmer using a MOSFET on the PWM output of a 16F87 - I have some IRF540A devices that I am using with a 1k res from the PWM out to Gnd as recommended in this thread - http://www.picbasic.co.uk/forum/showthread.php?t=2782.
What I am concerned about is that these are not Logic Level MOSFETs and I am mighty confused about the optimum drive for the MOSFET.
Based on a lot of google work and some stuff I have read I think I might have a problem with not enough drive to turn the Mosfet Hard On. I want to scale this up to do ~5A, but I am concerned that as I am only driving them with 5v that they might not be fully tuned on and this will cause the Ron to rise and also reduce the total current rating.
I know you could just say "Get some logic level mosfets", but here in Australia it is hard to find them without paying $8-9 each.
So any of you analog guys want to comment on driving ~5A from a 5v logic out on a IRF540A ??
bill.